KR102067546B1 - Organic device for X-ray detect and method of manufacturing the same - Google Patents

Abstract

Disclosed are an organic device for detecting X-rays and a method of manufacturing the same, which can improve signal acquisition efficiency of an organic device for detecting X-rays. In the case of the X-ray detection organic device including the active layer based on P3HT: PCBM, the absorbance of the X-rays irradiated due to the low absorption of visible light is converted to light by the scintillator and incident on the detection device. Although it has a low disadvantage, in order to improve the X-ray detection organic device that can improve the signal acquisition efficiency by improving the absorbance of the visible light region compared to the conventional P3HT: PCBM by using PCDTBT: PCBM as the material of the active layer and It provides a manufacturing method.

Description

Organic device for X-ray detection and its manufacturing method {Organic device for X-ray detect and method of manufacturing the same}

The present invention relates to an organic device for detecting X-rays and a method of manufacturing the same, and more particularly, to an organic device for detecting X-rays using PCDTBT: PCBM and a method of manufacturing the same.

In general, a high frequency digital X-ray imaging apparatus uses a direct conversion method that directly receives an electrical signal of a photoconductor to produce an image, and uses an optical signal of a scintillator to induce light of a scintillator. There is an indirect conversion method that converts a video into a video.

Conventionally, an X-ray detector based on a semiconductor inorganic material is generally used, and as a technique to replace, research on an organic material based detection device combining organic solar cell technology and X-ray technology has been conducted.

1 is a view showing a conventional organic device for detecting X-rays.

Referring to FIG. 1, a conventional X-ray detecting organic device 100 is formed on a substrate 110, a first electrode layer 120 formed on an upper surface of the substrate 110, and an upper portion of the first electrode layer 120. A hole transport layer 130 to improve the transport of the active layer 140 formed on the hole transport layer 130 and applied to form an electron-hole pair from the applied X-rays and the second electrode layer formed on the active layer 140 ( 150).

The conventional X-ray detection organic device 100 operates at a driving voltage of 1V or less, and when X-rays are applied, the conversion efficiency has a detection performance of about one hundredth of that of a semiconductor-based detector.

In addition, the conventional organic device 100 for detecting X-rays generally uses P3HT: PCBM as the active layer 140 material. However, in the indirect conversion method, the detection device to which the P3HT: PCBM active layer 140 is applied has a low detection efficiency for converting light that is converted and arrived from the scintillator back into an electric signal, and thus an improvement is required.

Korea Patent Registration 10-1412896

The present invention solves the problems of the prior art described above. That is, the present invention provides an X-ray detecting organic device and a method of manufacturing the same, which can improve signal acquisition efficiency based on superior absorbance compared to conventional materials.

The organic device for detecting X-rays of the present invention for solving the above problems is a substrate, a first electrode layer formed on the substrate, a hole transport layer formed on the first electrode layer, to improve the transport of holes, the hole transport layer An active layer formed on the substrate and absorbing visible light generated from the bottom of the substrate to generate an electron-hole pair, a second electrode layer formed on the active layer, and a substrate formed on the substrate, and converting X-rays to visible rays And a scintillator layer, wherein the active layer is formed of a mixture of PCDTBT: PCBM.

The PCDTBT: PCBM may be made of PCBM 2 to 4.5 parts by weight based on 1 part by weight of the PCDTBT.

The PCDTBT: PCBM may have 4 parts by weight of PCBM based on 1 part by weight of PCDTBT to have a high degree of matching compared to the spectral characteristics of the scintillator layer.

The active layer in which the PCDTBT: PCBM is mixed may have a thickness of about 65 nm to about 90 nm.

The active layer in which the PCDTBT: PCBM is mixed may have a thickness of 85 nm.

The scintillator layer may be formed of any one of a group consisting of Nal: TI, Csl: TI, Y 3 Al 5 O 12: Ce, CdWO 4, LuAG: Ce, and Gd 2 O 2 S: Tb.

The luminescence of the scintillator layer formed of the Csl: TI material and the absorbance of the active layer in which the PCDTBT: PCBM is mixed may overlap in the wavelength range of 500 to 650 nm.

The scintillator layer may have a thickness of 1 mm or less.

According to an aspect of the present invention, there is provided a method of manufacturing an organic device for detecting X-rays, the method comprising: forming a first electrode layer on a substrate, forming a hole transport layer on the first electrode layer, and a PCDTBT on the hole transport layer. : Forming an active layer formed of a mixture of PCBM, forming a second electrode layer on the active layer and forming a scintillator on the bottom of the substrate.

In the forming of the first electrode layer on the substrate, the substrate may be a non-alkali glass substrate coated with an ITO transparent electrode.

In the step of forming the active layer, the PCDTBT: PCBM may be made of PCBM 2 to 4.5 parts by weight based on 1 part by weight of the PCDTBT.

In the step of forming the active layer, the active layer mixed with the PCDTBT: PCBM may have a thickness of 65nm to 90nm.

In the step of forming the scintillator layer, the scintillator layer may be formed of any one of a group consisting of Nal: TI, Csl: TI, Y 3 Al 5 O 12: Ce, CdWO 4, LuAG: Ce, and Gd 2 O 2 S: Tb.

The luminescence of the scintillator layer formed of the Csl: TI material and the absorbance of the active layer in which the PCDTBT: PCBM is mixed may overlap in the wavelength range of 500 to 650 nm.

The method may further include performing an encapsulation process after forming the second electrode layer.

According to the present invention, by fabricating an X-ray detection device based on an organic material based on an indirect conversion method, it has advantages in terms of large area, economical efficiency, and fairness, compared to conventional semiconductor-based detection devices.

That is, in the case of an X-ray detection device including an active layer based on a mixture of P3HT: PCBM in the related art, the absorbed X-rays are irradiated by the scintillator to be incident on the detection device due to low absorbance of the visible light region. In case of having a low absorption rate, the X-ray detection device including the active layer based on the PCDTBT: PCBM mixture according to the present invention has an excellent absorbance of visible light region compared to the conventional P3HT: PCBM signal acquisition efficiency. There is an advantage to improve.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects that are not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view showing a conventional organic device for detecting X-rays.
2 is a view showing an organic device for X-ray detection of the present invention.
3 is a graph comparing the absorption curves of the two active layer materials (P3HT: PCBM, PCDTBT: PCBM) and the emission curves of the scintillator of the organic device for X-ray detection.
4 to 8 are views showing a method for manufacturing an organic device for detecting X-rays of the present invention.
9 is a graph showing the amount of charge detected upon X-ray exposure of the X-ray detection device according to the present invention.
10 is a graph showing the characteristics of the X-ray detection device of the indirect conversion method according to the PCDTBT: PCBM mixing ratio of the present invention.
11 is a graph showing the IPCE characteristics of the X-ray detection device according to the PCDTBT: PCBM mixing ratio of the present invention.
12 is a graph showing a change in characteristics according to the thickness of the active layer mixed with PCDTBT: PCBM of the present invention.
FIG. 13 is a graph for comparing sensitivity and dark current density of two active layer materials (P3HT: PCBM, PCDTBT: PCBM) of an organic device for X-ray detection.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and in the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and redundant description thereof will be omitted. Shall be.

Example

2 is a view showing the organic device for detecting X-rays 200 of the present invention.

2, the organic device 200 for detecting X-rays according to the present invention may include a substrate 210, a first electrode layer 220, a hole transport layer 230, an active layer 240, and a second electrode layer 250. And a scintillator layer 270, from which the scintillator layer 270 is formed, the scintillator layer 270, the substrate 210, the first electrode layer 220, the hole transport layer 230, the active layer 240, and the second electrode layer 250. It may be formed in the order of.

The substrate 210 may be formed of glass or plastic having flexibility. When the substrate 210 is a flexible plastic, the substrate 210 may be formed of any one of polyethylene terephthalate (PET), polyester (PES), polythiophene (PT), and polyimide (PI), aluminum foil, or stainless steel. It is formed from a flexible material that is a stainless steel foil and has flexibility. According to a preferred embodiment, the substrate 210 according to the present invention may be a non-alkali glass substrate 210 coated with an ITO transparent electrode.

The first electrode layer 220 may be formed on the substrate 210, and the first electrode layer 220 may be a transparent or conductive material. The material of the first electrode layer 220 may be indium tin oxide (ITO), antimony tin oxide (ATO), fluorine tin oxide (FTO), or aluminum-doped zinc oxide ( Al-doped Zinc Oxide: AZO) may be one or more selected from the group consisting of. Preferably, the first electrode layer 220 may be formed using indium tin oxide (ITO).

The hole transport layer 230 may be formed on the first electrode layer 220, and may improve charge transfer efficiency by improving an interface property between the active layer 240 and the first electrode layer 220. The material of the hole transport layer 230 may be a compound having the ability to transport holes, and excellent in thin film formation ability as well as blocking electrons. For example, the material of the hole transport layer 230 is TPD, PEDOT: PSS, G-PEDOT, PANI: PSS, PANI: CSA, PDBT, NPB, low molecular and polymer having an arylamine group (arylamine group), aromatic amine group It may be a low molecule and a polymer having an (aromatic amine group). As the method of forming the hole transport layer 230, a spin coating method, a spray coating method, a screen printing method, a bar coating method, a doctor blade coating method, a gravure printing method, or the like may be applied.

The active layer 240 may be formed on the hole transport layer 230. In the active layer 240, electrons and holes from the applied X-rays are separated and transported and injected into the respective electrodes. The active layer 240 may be implemented in various forms. The active layer 240 may have a single layer structure of a mixed thin film layer of a donor material and an acceptor material, and a two layer in which a donor material and an acceptor material are stacked. It may take the structure.

As donor materials, low molecular weight compounds such as phthalocyanine pigments such as copper phthalocyanine (CuPc), indigo, thioindigo pigments, melocyanine compounds and cyanine compounds, and polyparaphenylenevinylene (PPV); Conductive polymers including phenylene vinylene-based polymer derivatives such as), thiophene-based polymer derivatives such as polythiophene, PCPDTBT, P3HT, etc. may be used, but according to a preferred embodiment of the present invention PCPDTBT can be used.

Acceptor materials include fullerene (C60), ICBA, ICBM, PCBM, fullerene derivatives such as PC70BM, perylenes, perylene derivatives such as PTCBI, semiconductor nanoparticles such as CdS, CdSe, CdTe, or ZnSe Although may be used, according to a preferred embodiment according to the invention PCBM may be used as the acceptor material.

That is, a PCDTBT: PCBM mixture of a donor material PCPDTBT and an acceptor material PCBM may be used as the active layer 240 as the active layer 240 material of the organic device 200 for X-ray detection according to the present invention. For example, in the case of the organic detection device including the active layer 240 based on a mixture of P3HT: PCBM, the X-rays irradiated due to low absorbance of the visible light region are converted into light by the scintillator, and the When incident, the absorption rate is low, but the X-ray detection organic device 200 including the active layer 240 based on the PCDTBT: PCBM mixture according to the present invention, compared to the conventional P3HT: PCBM The absorbance of the visible light region is excellent, there is an advantage that can improve the signal acquisition efficiency.

3 is a graph comparing the absorption curves of the two active layer materials (P3HT: PCBM, PCDTBT: PCBM) and the emission curves of the scintillator of the organic device for X-ray detection.

Referring to FIG. 3, the emission curves of P3HT: PCBM, which is a conventional active layer material, and PCDTBT: PCBM, which is an active layer 240 material according to the present invention, are scintillators for an X-ray detection device based on an organic material based on an indirect conversion method. ) And a light emission curve.

As shown in the graph of FIG. 3, in the case of the active layer mixed with the conventional P3HT: PCBM, the absorbance decreases with increasing wavelength in the wavelength band of about 520 nm. It does not absorb. However, the active layer of the PCDTBT: PCBM mixed with the present invention shows relatively good absorbance compared to P3HT: PCBM in the entire visible region band, especially when considering the emission curve of the CsI (Tl) scintillator 56% compared to the peak level of 560nm. In the reduced region, 500nm to 650nm, the high degree of matching shows excellent characteristics for current generation due to the absorption of a lot of light.

In addition, it is preferable that the mixing ratio of PCDTBT: PCBM consists of 2 to 4.5 weight part PCBM with respect to 1 weight part of PCDTBT. More specifically, it is preferable that PCDTBT: PCBM has a weight ratio of 1: 4 in the weight ratio of PCDTBT and PCBM to have a high degree of matching compared to the spectral characteristics of the scintillator.

If less than 2 parts by weight of PCBM per 1 part by weight of PCDTBT, the collected current density (CCD) is lowered, so the detection sensitivity is rapidly decreased by more than 8% compared to the mixing ratio 1: 4, and the mixing ratio is 1: 1. Shows a 38% decrease in detection sensitivity. In addition, when 4.5 parts by weight or more of PCBM with respect to 1 part by weight of PCDTBT, the detection sensitivity is lost due to the increase of dark current density (DCD) and the decrease of collection current density. That is, when the mixing ratio of PCDTBT: PCBM is 1: 2 or less or 1: 4.5 or more, the detection sensitivity is reduced, so that an increase in dose of X-rays is required to improve detection sensitivity. Application of the line detector results in an increase in the amount of exposure to the patient.

Subsequently, the second electrode layer 250 may be formed on the active layer 240, and collects electrons, that is, receives electrons separated from the active layer 240. The material of the second electrode layer 250 may be, but is not limited to, one or more of a metal, an alloy, an electrically conductive compound, and a mixture thereof having a small work function. Specifically, the material of the second electrode layer 250 is aluminum (Al), zinc (Zn), titanium (Ti), indium (In), alkali metal, sodium-potassium (Na: K) alloy, magnesium-silver (Mg The alloy may be one or more than one of an alloy, a lithium-aluminum (Li / Al) double layer electrode, and a lithium fluoride-aluminum (LiF / Al) double layer electrode, but is not limited thereto. The second electrode layer 250 may be formed by DC sputtering, thermal evaporation, or alternatively by a wet method such as chemical vapor deposition (CVD), atomic layer deposition (ALD), electroplating, and various printing techniques. In addition, although omitted in FIG. 2, an electron transport layer (not shown) such as Alq3 may be further included between the active layer 240 and the second electrode layer 250 to increase the efficiency of acquiring the generated charge.

In general, the organic device for detecting X-rays is a direct conversion method for generating an image by directly receiving an electrical signal of a photoconductor and using a light collecting element to induce light from the scintillator layer 270. There is an indirect conversion method that converts a signal to produce an image. More specifically, in the case of the direct detection method, the charge generated in the active layer 240 of the organic device is measured by the incident X-rays. In the case of the indirect detection method, the scintillator layer 270 is attached to the detection device to illuminate the scintillator. The charge generated in the active layer 240 of the organic device is measured by the visible light converted by the layer 270.

In the organic device 200 for detecting X-rays according to the present invention, the scintillator layer 270 is formed under the substrate 210 of the organic device in order to apply the indirect conversion method. Therefore, X-rays incident by the formed scintillator layer 270 are changed into visible light, and the changed visible light reaches the active layer 240 to measure the charge generated in the active layer 240.

As a material that can be used for the scintillator layer 270, for example, Nal: TI, Csl: TI, Y3Al5O12: Ce, CdWO4, LuAG: Ce, Gd2O2S: Tb, etc. may be used. As described above, CsI: TI having a maximum emission of 540nm and a PL output of 59000photons / MeV may be used.

Density [g / cm ³ ] 4.51 Maximum emission [nm] 540 Lower wavelength cutoff [nm] 320 Refractive index at maximum emission 1.79 PL output (Photons / MeV) 59000

When CsI: TI is used as the scintillator layer, the scintillator layer preferably has a thickness of 1 mm or less. This is because the scintillator layer 270 thicker than 1 mm is due to the reason why visible light Photon generated inside the scintillator layer 270 is reabsorbed in the scintillator layer 270 or moved in a direction other than the rear surface. .

4 to 8 are views showing a method for manufacturing an organic device for detecting X-rays of the present invention.

4 to 8, in the manufacturing method of the organic device for detecting X-rays 200 of the present invention, forming the first electrode layer 220 on the substrate 210 and the upper portion of the first electrode layer 220. Forming a hole transport layer 230 in, forming an active layer 240 formed of a mixture of PCDTBT: PCBM on the hole transport layer 230, and forming a second electrode layer 250 on the active layer 240. And forming a scintillator layer 270 under the substrate 210.

In the forming of the first electrode layer 220 on the substrate 210, as shown in FIG. 4, a DC sputtering method or a chemical vapor deposition (CVD) atom on the transparent glass or the flexible polymer substrate 210 is different. The first electrode layer 220, which is a transparent electrode, may be formed by layer deposition (ALD), sol-gel coating, or electroplating. The substrate 210 undergoes a cleaning process immediately before use, and may be ultrasonically cleaned after soaking in acetone, alcohol, water, or a mixed solution thereof. The thickness of the transparent electrode may be preferably 100 ~ 1,000nm. In addition, the substrate 210 used may preferably be a non-alkali glass substrate 210 coated with an ITO transparent electrode.

Forming the hole transport layer 230 on the first electrode layer 220 as shown in Figure 5, the spin coating method, spray coating method, screen printing method, bar (bar) on the first electrode layer 220 A hole transfer layer (HTL) 230 may be formed using a coating method, a doctor blade coating method, a gravure printing method, or the like. The hole transport layer 230 formed as described above may have a thickness of about 5 nm to about 300 nm. The material for the hole transport layer 230 is TPD, PEDOT: PSS, G-PEDOT, PANI: PSS, PANI: CSA, PDBT, NPB, a low molecular and polymer having an arylamine group (arylamine group), aromatic amine group (aromatic amine group It may be a low molecule and a polymer having a).

In the step of forming the active layer 240 formed of PCDTBT: PCBM on the hole transport layer 230, the active layer 240 is a phthalocyanine-based pigment, such as copper phthalocyanine (CuPc) as a donor material, indigo, thioindigo-based pigments, Low molecular weight compounds such as melocyanine compounds and cyanine compounds, and phenylenevinylene-based polymer derivatives such as poly-ρ-phenylenevinylene (PPV), thiophenes such as polythiophene, PCPDTBT, and P3HT. A conductive polymer including a polymer derivative may be used, but according to a preferred embodiment of the present invention, PCPDTBT may be used as a donor material. In addition, acceptor materials include fullerene (C60), ICBA, ICBM, PCBM, fullerene derivatives such as PC70BM, perylene derivatives such as perylene, PTCBI, semiconductors such as CdS, CdSe, CdTe, or ZnSe Nanoparticles can be used, but according to a preferred embodiment according to the invention PCBM may be used as the acceptor material.

That is, a PCDTBT: PCBM mixture of a donor material PCPDTBT and an acceptor material PCBM may be used as the active layer 240 as the active layer 240 material of the organic device 200 for X-ray detection according to the present invention. Here, it is preferable that PCDTBT: PCBM consists of 2 to 4.5 weight part of PCBM with respect to 1 weight part of PCDTBT. More specifically, it is preferable that PCDTBT: PCBM has a weight ratio of 1: 4 in the weight ratio of PCDTBT and PCBM to have a high degree of matching compared to the spectral characteristics of the scintillator.

When the active solution is formed using the PCDTBT: PCBM, the active solution is formed by spin coating, spray coating, screen printing, bar coating, doctor blade coating, and gravure printing on the hole transport layer 230. ). The active layer based X-ray detection organic device 200 including the PCDTBT: PCBM mixture thus formed has better absorbance in the visible region than the active layer based X-ray detection organic device including the P3HT: PCBM mixture. The signal acquisition efficiency can be improved.

In the forming of the second electrode layer 250 on the active layer 240, as illustrated in FIG. 7, the second electrode layer (not shown) receives the electrons separated from the active layer 240 on the active layer 240 ( 250) is formed. The second electrode layer 250 is made of aluminum (Al), zinc (Zn), titanium (Ti), indium (In), alkali metal, sodium-potassium (Na: K) alloy, magnesium-silver (Mg: Ag) alloy , Lithium-aluminum (Li / Al) double layer electrode, lithium fluoride-aluminum (LiF / Al) double layer electrode may be a metal electrode, the DC sputtering method on the active layer 240, thermal evaporation or otherwise chemical vapor deposition ( CVD), atomic layer deposition (ALD), electroplating and wet methods such as various printing techniques. Although not shown, an electron transport layer (not shown) such as Alq3 is formed on the active layer 240 to increase the efficiency of acquiring the generated charges between the active layer 240 and the second electrode layer 250. It may be further formed in a manner or the like.

After forming the second electrode layer 250, the method may further include performing an encapsulation process. In the encapsulation process, the encapsulation layer 260 encapsulates the outside of the first electrode layer 220, the hole transport layer 230, the active layer 240, and the second electrode layer 250 to protect the organic device from moisture and oxygen in the air. Can be formed.

The forming of the scintillator layer 270 under the substrate 210 is performed by forming the encapsulation layer 260 by the encapsulation process described above, as shown in FIG. 9, and then fabricating the organic device and the scintillator layer 270. The scintillator layer 270 may be formed under the substrate 210 of the organic device by using an optical glue to minimize optical loss between the layers.

Experimental Example

9 is a graph showing the amount of charge detected upon X-ray exposure of the X-ray detection device according to the present invention.

Referring to FIG. 9, the experimental example according to the present invention shows the performance of the device through the amount of charge generated when X-rays are irradiated by turning on and off X-rays in an indirect type detection device manufactured based on PCDTBT: PCBM. The evaluation was carried out. The amount of charge generated when X-rays were irradiated by applying a DC voltage of 0.2 to 1.0 V to the organic device 200 of the present invention under the conditions of applying a tube voltage of 80 kVp and 63 mAs, which is mainly used for medical purposes, was measured at the cathode. It was.

As shown in FIG. 9, it can be seen that as the applied voltage increases from 0.2V to 1.0V, the amount of charge measured at the cathode increases.

Based on the measured charge amount, the collected current density (Collected Current Density, CCD), the dark current density (Dark Current Density, DCD) and the X-ray detection sensitivity of the X-ray detection device 200 of the indirect conversion method according to the present invention. (Sensitivity) can be calculated separately.

Equation 1 for calculating the collection charge density is shown in Equation 1.

Here, Exposed Time [s] * Detection Area [cm ² ] means X-ray detection area, and Charges during X-rayON [nC] means measured amount of charge when X-rays are irradiated.

In addition, a formula for calculating the dark current density is shown in Equation 2, and a formula for calculating the detection sensitivity is shown in Equation 3, respectively.

Here, Absorbed Dose [Gy] denotes a coating dose, and Detection Area [cm ² ] denotes an X-ray detection region, and Currentduring X-ray ON means an amount of electric charge measured when X-rays are irradiated.

An active layer formed of a conventional P3HT: PCBM mixed material using the collection current density, the dark current density, and the X-ray detection sensitivity of the X-ray detection device including the active layer formed of the PCDTBT: PCBM mixed material according to the present invention. The comparison experiment was performed by selecting the X-ray detection device comprising a comparison group.

10 is a graph showing the characteristics of the X-ray detection device of the indirect conversion method according to the PCDTBT: PCBM mixing ratio of the present invention.

Referring to FIG. 10, the collection current density, the dark current density, and the X-ray detection sensitivity characteristics of the PCDTBT: PCBM mixing ratio were measured from 1: 2 to 1: 4.5. In particular, the ratio of PCDTBT: PCBM mixing ratio was 1: 4, the collecting current density ^{(CCD) = 215.23nA / cm 2} , the dark current density (DCD) = 7.59 nA / cm 2, X- ray detection sensitivity (sensitivity) = the most excellent characteristics represented by a 1.55mA / Gy · ² from You can check it.

That is, when the mixing ratio is 1: 2 or less, as shown in FIG. 10, since the collection current density is lowered, the detection sensitivity is sharply reduced by more than 8% compared to the mixing ratio 1: 4 having the highest detection sensitivity. The sensitivity tends to decrease by 38%. In addition, when the mixing ratio is 1: 4.5 or more, the detection sensitivity is lost due to the increase in the dark current density and the decrease in the collection current density. That is, when the mixing ratio of PCDTBT: PCBM is 1: 2 or less, or 1: 4.5 or more, the detection sensitivity is reduced, so that an increase in dose of X-rays is required to improve detection sensitivity. Application of the -ray detector results in an increase in the amount of exposure to the patient.

11 is a graph showing the IPCE characteristics of the X-ray detection device according to the PCDTBT: PCBM mixing ratio of the present invention.

Referring to FIG. 11, FIG. 11 is a graph measuring the spin rate at 1100 rpm, changing the mixing ratio of PCDTBT: PCBM, and measuring the Incident Photon-to-Current Efficiency (IPCE) characteristics.

As shown in FIG. 11, it can be seen that IPCE characteristics of the ratio of PCDTBT: PCBM in the range adjacent to the emission wavelength of the scintillator are relatively excellent in the range of 1: 2 to 1: 4.5. In addition, it can be seen that the best IPCE characteristic appears at 1: 4 in the mixing ratio of PCDTBT: PCBM. Accordingly, it can be seen that the active layer having the mixing ratio of PCDTBT: PCBM 1: 4 can improve the detection sensitivity of the X-ray detection element when combined with the scintillator.

12 is a graph showing a change in characteristics according to the thickness of the active layer mixed with PCDTBT: PCBM of the present invention.

Referring to FIG. 12, FIG. 12 is an experimental result of changing the thickness of an active layer formed at a 1: 4 mixing ratio having the best characteristics among the mixing ratios of PCDTBT: PCBM, and the collection current density and the dark current according to the thickness change of the active layer. The result of measuring density and X-ray detection sensitivity is shown.

As shown in Figure 12, it can be seen that the thickness of the active layer mixed with PCDTBT: PCBM is improved in the collection current density, dark current density and X-ray detection sensitivity in the range of 65nm ~ 90nm. If the thickness of the active layer is less than 65 nm, the detection sensitivity tends to decrease as shown in FIG. 12 due to the rapid increase of dark current density (more than 98% of the thickness of 85 nm) due to the thin thickness, and the thickness of the active layer is 90 nm. With the above thickness, in the case of the X-ray detector, the detection sensitivity decreases due to the decrease in the collection current density due to the loss generated by the charge generated in the active layer moving to the electrode. Therefore, when the thickness of the active layer is greater than 90nm, since the dose of X-rays is required to increase the detection sensitivity, the exposure dose to the patient is increased.

Moreover, when the thickness of the active layer mixed with PCDTBT: PCBM was 85 nm, the collection current density was 235.58 nA / cm ² , the dark current density was 9.68 nA / cm ² , and the X-ray detection sensitivity was 1.69 mA / Gy ·. It can be seen that the best characteristic is shown as ² .

FIG. 13 is a graph for comparing sensitivity and dark current density of two active layer materials (P3HT: PCBM, PCDTBT: PCBM) of an organic device for X-ray detection.

In addition, data according to the graph shown in FIG. 13 is shown in Table 2.

Active Layer Materials Sensitivity
[nC / mR * cm ² ] Dark CurrentDensity
[nA / cm ² ] P3HT: PCBM 1.12 11.49 PCDTBT: PCBM 1.69 9.68 Rate of change + 33.7% -18.7%

Referring to FIG. 13 and Table 2, in the case of the PCDTBT: PCBM-based X-ray detecting organic device 200 according to the present invention, X- under the same voltage condition as compared to the conventional P3HT: PCBM-based X-ray detecting organic device. It can be seen that the line detection sensitivity is improved by 33.7%. In the case of the dark current (current measured by the organic detection device when the same voltage is applied in the absence of X-rays), the effect of decrease of 18.7% can be confirmed.

As described above, in the case of the organic device for detecting X-rays including the active layer 240 based on the mixture of P3HT: PCBM, the X-rays irradiated due to low absorbance of the visible region are emitted by the scintillator. Absorption rate is low when it is converted into the incident to the detection element, but the X-ray detection organic device 200 including the active layer 240 based on the PCDTBT: PCBM mixture according to the present invention Compared with the conventional P3HT: PCBM, the absorbance of the visible light region is excellent, so that the signal acquisition efficiency can be improved.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples for clarity and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

210: substrate 220: first electrode layer
230: hole transport layer 240: active layer
250: second electrode layer 260: encapsulation layer
270: scintillator layer

Claims (15)

Board;
A first electrode layer formed on the substrate;
A hole transport layer formed on the first electrode layer and improving hole transport;
An active layer formed on the hole transport layer and absorbing visible light generated from the lower portion of the substrate to generate an electron-hole pair;
A second electrode layer formed on the active layer; And
And a scintillator layer formed of Csl: TI under the substrate and converting X-rays into visible light.
The active layer,
1 to 4 parts by weight of PCBM 3 parts by weight of PCDTBT in consideration of the match between the spectrum emission spectrum of the Csl: TI having an emission peak at a wavelength of 560 nm and the absorbance curve of the active layer PCDTBT: formed of a mixture of PCBB,
The active layer formed of a mixture of the PCDTBT: PCBM is an organic device for X-ray detection having a thickness of 80nm to 90nm. delete The method of claim 1,
Wherein said PCDTBT: PCBM has 4 parts by weight of PCBM based on 1 part by weight of PCDTBT to have a high degree of matching compared to the spectral characteristics of the scintillator layer. delete The method of claim 1,
The PCDTBT: PCBM is mixed with the active layer is an organic device for X-ray detection having a thickness of 85nm. delete The method of claim 1,
And an absorbance of the scintillator layer formed of the Csl: TI material and an absorbance of the active layer in which the PCDTBT: PCBM is mixed are overlapped in the wavelength range of 500 to 650 nm. The method of claim 1,
The scintillator layer has an thickness of 1 mm or less. Forming a first electrode layer on the substrate;
Forming a hole transport layer on the first electrode layer;
Forming an active layer on the hole transport layer;
Forming a second electrode layer on the active layer; And
Forming a scintillator layer formed of Csl: TI under the substrate,
The active layer,
Considering the match between the spectrum emission curve of Csl: TI having an emission peak at a wavelength of 560 nm and the absorbance curve of the active layer, it consists of 3 parts by weight of PCBM to 4 parts by weight based on PCDTBT. PCDTBT: formed of a mixture of PCBBM,
The active layer formed of a mixture of the PCDTBT: PCBM has a thickness of 80nm to 90nm manufacturing method of the organic device for X-ray detection. The method of claim 9, wherein in the forming of the first electrode layer on the substrate,
Wherein the substrate is a non-alkali glass (Ion-Alkali Glass) substrate coated with an ITO transparent electrode manufacturing method of the organic device for X-ray detection. delete delete delete The method of claim 9,
And a light absorbency of the scintillator layer formed of the Csl: TI material and an absorbance of the active layer in which the PCDTBT: PCBM is mixed are overlapped in a wavelength range of 500 to 650 nm. The method of claim 9,
A method of manufacturing an organic device for detecting X-rays, further comprising performing an encapsulation process after forming the second electrode layer.

Images